三维CT对颈内动脉硬膜环附近动脉瘤的诊断

Three-dimensional CT angiography for the diagnosis of juxta-dural ring aneurysms

目的总结应用三维CT血管造影(3D-CTA)对颈内动脉硬膜环附近动脉瘤(juxta-dural ring aneurysm, JDRAn)的诊断经验。方法分析23例该部位动脉瘤患者的26个动脉瘤与海绵静脉窦及硬脑膜的位置关系,评价3D-CTA在判定动脉瘤是否向硬膜内突出上的作用。结果3D-CTA诊断出26个JDRAn中的25个,诊断率为96%。仅在高CT值表面遮盖显示法(shaded surface display,SSD)处理影像上显示的6个动脉瘤均位于硬膜外;6个颈内动脉窦部动脉瘤(carotid cave aneurysm, CCAn)中3个位于硬膜内,1个位于硬膜外,另2个颈部的一部分突出于硬膜内。低CT值处理影像上显示的其它13个非CCAn均突出于硬膜内。结论3D-CTA可以有效地诊断JDRAn,为手术适应证的选择提供有益的参考。

Objective To evaluate the image quality of three-dimensional CT angiography (3D-CTA) for the diagnosis whether juxta-dural ring aneurysms are located intradurally or extradurally. Methods 3D-CTA was performed on 23 cases with 26 juxta-dural ring aneurysms with the high does infusion method. The three-dimensional images were obtained with the shaded surface display through both lower (120HU-180HU) and higher (250HU-350HU) threshold processing. Results Twenty-five of 26 aneurysms were demonstrated by our protocol, thus indicating the correct diagnostic rate of 96%. Only one transitional aneurysm originating from the clinoidal segment of the ICA just beneath the anterior clinoid process was not detected. 3D-CTA is superior to DSA for the better understanding of the anatomical localization, direction and shape of the aneurysms. All of the intradural aneurysms were depicted with the lower threshold processing. On the other hand, the extradural aneurysms were apparently demonstrated with the threshold of 250HU eliminating the venous sinuses and the overlapped dura matter. Conclusion High does infusion method of 3D-CTA is useful for the diagnosis of the anatomical location of juxta-dural ring ICA aneurysms.